A number of known organic synthesis processes require separation and recovery of expensive complex metal catalysts from a homogeneous organic and/or aqueous reaction mixture. Such processes include hydroformylation, hydrocylation (intramolecular and intermolecular), hydrocyanation, hydroamidation, hydroesterification, aminolysis, alcoholysis, carbonylation, olefin isomerization, transfer hydrogenation and the like. Many of these processes involve reaction of organic compounds with carbon monoxide, or with carbon monoxide and additional reactants such as hydrogen, or with hydrogen cyanide, in the presence of a suitable metal complex catalyst. Such processes, including the identification of suitable reactants and process conditions are well known in the chemical art and are described in various literature references such as Kirk-Othmer, Encyclopedia of Chemical Technology, Fourth Edition, 1996.
The metal complex catalysts useful in such organic synthesis processes are also well known and described in the literature. Such catalysts generally comprise an appropriately selected metal which is complexed with one or more suitable ligands. Examples of metals which can be used in such processes include Group 8, 9 and 10 metals such as rhodium (Rh), cobalt (Co), iridium (Ir), ruthenium (Ru), iron (Fe), nickel (Ni), palladium (Pd), platinum (Pt), osmium (Os) and mixtures thereof. Other useful metals include Group 6 metals such as chromium (Cr), molybdenum (Mo), tungsten (W) and mixtures thereof. The preferred and most commonly used metals are rhodium, cobalt and ruthenium, especially rhodium. A wide variety of compounds useful as ligands in the metal complex catalysts are also well known in the art and described in the literature. Phosphorus containing organic compounds have been found to be particularly useful as ligands.